Beam presses

ABSTRACT

A press or guillotine having a beam-type working head which is displaceable by hydraulic thrust means via at least one pair of toggle struts. At the end of a working stroke the included angle defined by the struts exceeds 150*. One of the struts may form the working arm of a lever of the second order whose effort arm is connected to the thrust means. Matched pairs of sturts may be used, operable by matched thrust means.

tlnited States Patent [191 De Jager Nov. 13, 1973 1 BEAM PRESSES [76] Inventor: Frederik Johannes De Jager, Orange Free State Province, Kestell, Republic of South Africa 22 Filed: Oct.20, 1971 21 Appl. No.: 190,853

[30] Foreign Application Priority Data Oct 30, 1970 South Africa 707397 [52] US. Cl. 74/520, 100/293 [51] Int. Cl G05g 1/04 [58] Field of Search 74/520; 100/283, 100/293, 294

[56] References Cited UNITED STATES PATENTS 1,981,198 11/1934 Rupp 100/293 3,654,811 4/1972 Peterson 74/520 2,624,915 l/1953 Corson 74/520 2,338,379 l/1944 Henke 74/520 2,269,308 1/1942 Gates 1 1. 74/520 1,873,694 8/1932 Wilkins0n.... 74/520 1,451,292 4/1923 Dashew 74/520 1,042,381 10/1912 Baker 74/520 2,318,814 5/1943 Strong 74/520 Primary Examiner-Charles J. Myhre Assistant Examiner-R. H. Lazarus Att0rneyS. Delvalle Goldsmith et a1.

[5 7] ABSTRACT A press or guillotine having a beam-type working head which is displaceable by hydraulic thrust means via at least one pair of toggle struts. At the end of a working stroke the included angle defined by the struts exceeds 150. One of the struts may form the working arm of a lever of the second order whose effort arm is connected to the thrust means. Matched pairs of sturts may be used, operable by matched thrust means.

5 Claims, 2 Drawing Figures PATENTEDHUV 13 m 3771; 386

FIQ, I.

BEAM PRESSES This invention relates to a press or guillotine. In such a machine a working head carrying a tool is displaced in relation to a fixed tool or table. In particular, the invention relates to a beam press or guillotine, suitable for bending, cutting, or otherwise shaping sheets or plates.

In machines known to the applicant, the thrust from a thrustor is applied directly or via a lever to a working head. This means that for a given resistance an equivalent or corresponding thrust is necessary to perform the job.

It is an object of the present invention to provide a machine which permits the use of a thrustor of a lower capacity than the resistance which the working head has to overcome.

According to the invention, a machine of the kind described, comprises thrust means; and a strut system comprising at least one pair of struts (being an anchor strut and a working strut) pivotally connected together toggle fashion at their inner ends, the outer end of the anchor strut being pivotally connected to an anchor point, and the outer end of the working strut being pivotally connected to a working head guided for linear movement; the said working strut constituting the working arm of a lever of the second order, and the thrust means being pivotally connected to the effort arm of the said lever and being adapted by displacing the effort arm to displace the pivotally connected inner ends of the pair of struts toggle fashion, the said pivotally connected inner ends constituting a floating fulcrum for the lever.

The strut which is pivotally connected to the head may constitute the working arm of a lever, the thrust means being connected to the effort arm of the lever. The lever may be of the first order or of the second order. When the lever is of the second order, then the inner end of the strut connected to the strut constituting the working arm of the lever provides a floating fulcrum to the lever.

The strut system may comprise a matched pair of strut pairs operatively connected to the head.

The thrust means may include a plunger and cylinder assembly adapted for operative displacement by a working fluid under pressure.

The strut system may comprise a matched pair of strut pairs operatively connected to the head. The thrust means may include a matched pair of plunger and cylinder assemblies operable in parallel from a single source of working fluid under pressure.

The invention will now be described by way of example with reference to the accompanying drawings.

In the drawings:

FIG. 1 shows diagrammatically a front view of a beam press according to the invention; and

FIG. 2 shows a detailed front view of the thrust means of the press shown in FIG. 1.

Referring now to FIGS. 1 and 2 of the drawings, there is shown a beam press 10.5 embodying the principle of operation of FIG. 4. The press comprises a fixed frame secured to a floor 32. A working head in the form of a beam 20.5 is mounted for up and down movement in the frame 30 in the direction of arrow 22. The working face 20.51 of the beam 20.5, is arranged to contact a work piece (not shown) which is located on a working platform or base 34.

The movement of the beam is controlled by a pair of matched hydraulic thrustors 12.1 and 12.2, which are operable in parallel by means of hydraulic fluid under pressure, supplied via pipes 36. The strut 16.2 and arm 16.4 are provided by a lever of the second order in the form of a plate 16.6. Likewise, the strut 18.2 and the arm 18.4 are provided by another lever of the second order in the form of a plate 18.6. The struts 16.1 and 18.1 are referred to as anchor struts, and the working arms 16.2 and 18.2 of the levers are referred to as working struts.

The full lines in FIGS. 1 and 2 show the working head 20.5 in its displaced position, that is at the end of its working stroke whereas the dotted lines shown the struts, and working head at the end of its return stroke. The levers 16.6 and 18.6, are provided with stops to limit their pivotal displacement, and thus to limit the movement of the pivotal connections 16.3 and 18.3 in the direction of arrows 16.31 and 18.31 so that the included angle between the struts of a pair does not exceed 180.

It is an advantage of this invention, that the toggle action of the struts 16.1 and 16.2, and 18.1 and 18.2, ensures that a very high pressure can be exerted by a working head at the end of its working stroke, that is when the included angle defined between the struts approaches 180.

The applicant has found that with a beam press in accordance with the invention, a considerably lower thrustor capacity is adequate to perform a given job when compared with conventional beam presses known to the applicant. This results in a lower cost of the hydraulic equipment of the press, when compared with conventional presses known to the applicant.

What I claim is:

1. A machine of the kind described, which comprises thrust means; and a strut system comprising at least one pair of struts one an anchor strut and the other being a working strut, pivotally connected together toggle fashion at their inner ends, the outer end of the anchor strut being pivotally connected to a working head guided for linear movement; the said working strut having a working arm connected thereto and forming with said working strut a lever of the second order, and the thrust means being pivotally connected to the working arm of the said lever and being adapted by displacing the effort arm to displace the pivotally connected inner ends of the pair of struts toggle fashion, the said pivotally connected inner ends constituting a floating fulcrum for the lever.

2. A machine as claimed in claim 1, in which the angular disposition of the pair of struts is such that at the end of a working stroke the included angle defined by lines joining the pivotal axes of the pair of struts exceeds 3. A machine as claimed in claim 1, in which the strut system comprises a matched pair of strut pairs operatively connected to the head.

4. A machine as claimed in claim 1, in which the thrust means includes a plunger and cylinder assembly adapted for operative displacement by a working fluid under pressure.

5. A machine as claimed in claim 1, in which the strut system comprises a matched pair of strut pairs operatively connected to the head, and in which the thrust means includes a matched pair of plunger and cylinder assemblies operable in parallel from a single source of working fluid under pressure. 

1. A machine of the kind described, which comprises thrust means; and a strut system comprising at least one pair of struts one an anchor strut and the other being a working strut, pivotally connected together toggle fashion at their inner ends, the outer end of the anchor strut being pivotally connected to a working head guided for linear movement; the said working strut having a working arm connected thereto and forming with said working strut a lever of the second order, and the thrust means being pivotally connected to the working arm of the said lever and being adapted by displacing the effort arm to displace the pivotally connected inner ends of the pair of struts toggle fashion, the said pivotally connected inner ends constituting a floating fulcrum for the lever.
 2. A machine as claimed in claim 1, in which the angular disposition of the pair of struts is such that at the end of a working stroke the included angle defined by lines joining the pivotal axes of the pair of struts exceeds 150*.
 3. A machine as claimed in claim 1, in which the strut system comprises a matched pair of strut pairs operatively connected to the head.
 4. A machine as claimed in claim 1, in which the thrust means includes a plunger and cylinder assembly adapted for operative displacement by a working fluid under pressure.
 5. A machine as claimed in claim 1, in which the strut system comprises a matched pair of strut pairs operatively connected to the head, and in which the thrust means includes a matched pair of plunger and cylinder assemblies operable in parallel from a single source of working fluid under pressure. 